Add compiler:c++11-lang to USES to fix build on GCC-based systems:
cc1: error: unrecognized command line option "-Wpedantic" cc1: error: unrecognized command line option "-Wno-gnu-case-range" cc1: error: unrecognized command line option "-Wno-gnu-conditional-omitted-operand" cc1: error: unrecognized command line option "-std=c11"
Approved by: portmgr (tier-2 blanket)